Cog type v belt



Jan. 20, 1953 E. NASSIMBENE llf.

COG TYPE V BELT Filed Oct. 19, 1950 Bnvzntor ERNEST NASSIMBENE @za/.geom 9/ M attorneys Patented Jan. 20, 1953 COG TYPE V BELT -Ernest Nassimbene, Denver, Colo., assignor to The Gates Rubber Company, Denver, Colo.,v a

corporation of" Colorado Application October 19, 1950, Serial No. 190,998

3 Claims.

This invention relates to power transmission belts and more particularly to improvements in cog-type V-belts.

One of the objects of the invention is to provide a cog-type V-belt in which cracking ofthe belt in the regions between the cogs is minimized, thereby increasing the usefullife of the belt.

Another object is to minimize belt cracking by novel wall construction connecting adjacent cogs.

Further objects, advantages, and salient features will become .more apparent from the .description to follow, the appended claims, and the accompanying drawing, in which:

Figure 1 is a diagrammatic side elevation of a belt transmission system employing the belt which constitutes the subject of the invention;

Figure 2 is an enlarged fragmentary side elevation of the belt shown in Figure l;

Figure 3 is a section taken on. line -3, Figure 2;

Figures 4, 5 and 6 are enlarged fragmentary side elevations of various forms of the belt shown in Figure 2;

Figure '7 is a fragmentary side elevation of one form of prior art belt;

Figure 8 is a side elevation of another form of prior art belt; and

Figure 9 is an enlarged side elevation of Figures 7 and 8, and any of Figures 4, 5 or 6, superposed upon each other.

Referring to the drawing, Figure 1 illustrates any conventional V-pulleys II), I I which transmit power, one to the other, by a belt I2, this being of the so-called cog-type having a plurality of spaced cogs I3 thereon.

The internal construction of belt I2 is conventional, and as exemplary only, has been shown in Figure 3 with rubberized reinforcing fabric layers I4, a tension cord section I5, and a fabric cover I6, the parts all being vulcanized together as well understood in the art.

For a better understanding of the invention, reference is now made to Figures 7 and 8. Figure '7 illustrates one form of prior art cog belt I2a wherein a semi-circular wall Ila of radius Ra extends between adjacent cogs I3a. This type of belt usually commences to crack approximately midway between cogs, as shown by crack Ilia.. Figure 8 illustrates another form of prior art cog belt I2b wherein the wall which extends between adjacent cogs comprises a at or planar portion IIb and arcuate end portions llc, of relatively small radius Rb. This type of belt usually commences to crack in the fillets formed by portions llc, as shown by cracks |817. It has been found that the cracking of the belts just referred to can be minimized and the life of a belt thus materially increased by the form of wall construction of this invention, which will now be described and distinguished from the prior art.

Referring to Figures 4, 5 and 6., it will be observed that .the llets are much the same as fillets I'Ic of Figure :8, but wall Il between the fillets is arched upwardly, rather than being planar, as in Figure .8. It also differs from Figure '7 in that it is of ,larger radius of curvature Vl?. than radius Ra. Figure 9 illustrates the three shapes so far described superposed upon reach other and makes apparent their differences.

It has .been found, that the curvature of wall I'I may Vary somewhat and produce optimum results so long as its shape remains within certain general limits. In Figure 4 it is shown as a simple circular arc of relatively large radius R having its center on a line perpendicular to the longitudinal axis of the belt, the line intersecting the central portion of wall I1, the ends of the arc joining the arcuate portions defined by relatively small radius Rb, Rb.

In Figure 5 wall I1 is similar to that shown in Figure 4 except that the radius of curvature decreases, as shown by R1, as the curve approaches the portions defined by Rb, Rb.

Figure 6 is similar to Figure 5 in that the radius of curvature also decreases, but the center of curvature may be at points other than along the central transverse belt axis between cogs.

A special form of curve between cogs within the purview of the invention and which may be defined with mathematical exactness is a semi-ellipse having a relatively large major axis and a relatively small minor axis, the major axis being parallel to the longitudinal axis of the belt.

Belts built in accordance with this invention will not commence to crack at any particular point such as shown at Ia or Ib of Figures 7 and 8, which indicates that the upwardly arched portion I1 minimizes localized stress concentrations and more uniformly distributes the stresses on the belt cover and core of the belt throughout the length of the wall between cogs as the belt flexes in passing over the pulleys.

Various modifications within the purview of the invention will become apparent to those skilled in the art, and the specic constructions illustrated are to be considered as exemplary only and the invention not limited thereto except as defined by the scope of the appended claims.

Having described the invention, what is claimed as new is:

l. In a V-belt of the type having a plurality of spaced cogs disposed on the narrow side thereof, each cog having an exposed end surface adapted to face a V-pulley, the belt being constructed of rubber-like material provided with a reinforced tension section in the wider side thereof, the improvement which comprises; a wall disposed between adiacent cogs extending transversely between the pulley engaging sides of the belt, said wall having a concave central portion joined at its ends to the adjacent cogs by concave end portions, the radius of curvature of the central portion at all portions thereof being greater than the radius of curvature of the end portions.

2. In a V-belt of the type having a plurality of spaced cogs disposed on the narrow side thereof, each cog having an exposed end surface adapted to face a V-pulley, the belt being constructed of rubber-like material provided with a reinforced tension section in the wider side thereof, adjacent cogs having a wall disposed therebetween extending transversely between the pulley engaging sides of the belt, said wall having a central portion joined at its ends to the adjacent cogs by concave end portions,.the improvement wherein said central portion is concave and its radius of curvature at all portions between the ends thereof is greater than the radius of curvature of said end portions,

3. In a V-belt of the type having a plurality of spaced cogs disposed on the narrow side thereof, each cog having an exposed end surface adapted to face a V-pulley, the belt being constructed of rubber-like material provided with a reinforced tension section in the wider side thereof, adja- 25 cent cogs having a wall disposed therebetween extending transversely between the pulley engaging sides of the belt, said wall having a central portion joinedvat its ends to the adjacent cogs by concave end portions, said end portions being subjected to stress concentrations undei` belt exure tending t0 crack the belt thereat, the improvement wherein said central portion is concave and of greater radius of curvature than said end portions and of a shape adapted to reduce said stress concentrations.

ERNEST NASSIMBENE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

